Molecular Interferometry Makes a New Break

Abstract

Quantum mechanics has been spectacularly successful in explaining the microscopic realm, yet exactly how it interfaces to the everyday macroscopic world is still an open question. To this end, a long-standing goal in physics has been to realize a system like that envisaged by Erwin Schrodinger in the early days of quantum mechanics in which a large object like a cat simultaneously exists in two separate states (such as “dead” and “alive”) [1]. Schrodinger originally proposed his famous “gedanken experiment” to point out a problem with quantum theories that allow for the existence of cat states and other macroscopic superpositions, which in fact do not appear in everyday life. While progress has been made in exploring the quantum-classical boundary with nanomechanical systems [2], much still remains to be done. Now physicists at the University of Vienna, Austria, have developed a new technique for observing quantum effects in the external motion of large molecules. Nadine Dorre and co-workers used three standing waves of UV light as the optical elements in a matter-wave interferometer for molecules with masses as high as 2000 atomic mass units (amu) [3]. The method can potentially be extended to the interference of larger particles, such as complex organic molecules and even small “living” organisms like viruses.